Four days before previews, the cast and crew of the new Broadway version of “Breakfast at Tiffany’s” were putting the finishing touches on the show’s blocking, lighting and costumes. But on this final day of February, there remained one gaping hole: the director still hadn’t cast the role of Holly Golightly’s cat.

It is not, thankfully, a speaking role. But the requirements are stiff. Just as Holly’s cat plays a key part in the Truman Capote novella, it does in this new Richard Greenberg adaptation. It must be handed from one actor to another, sit during a party scene as Holly explains that it is nameless because it doesn’t belong to anyone, and walk offstage. Near the end, saying they are both independents who never made each other any promises, Holly tosses it onto a city street, and the cat must run into the wings.

So the role requires not only an animal that can handle lights, microphones and an audience, but also one that can cross the stage, sit, stay and exit on cue. In short, it requires a dog.

The 1961 film version of “Breakfast at Tiffany’s,” with its star turn by Audrey Hepburn as a New York party girl, may be part of the Library of Congress’s National Film Registry, but stage productions haven’t proved as memorable. A 1966 musical was pulled during previews when the producer David Merrick decided it was “excruciatingly boring.” The director of this version, Sean Mathias, oversaw a different adaptation in London in 2009 that received middling reviews. And in January a major investor pulled out of this production, but producers wooed him back, and the show will go on, with its opening night on March 20, assuming that the cat will go on.